Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir. In a variety of well operations, mud motors are used to convert flowing mud into rotary motion. The rotary motion can be used to drive a drill bit during a drilling operation. Mud motors generally are designed as Moineau motors, i.e. progressive cavity motors, which employ a helical rotor within a corresponding stator. The helical rotor is rotated by fluid flow through the mud motor between the helical rotor and the corresponding stator.